Dissolving electronics are a surprisingly simple answer to implantable tech

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Despite the many things in our lives that we already have DARPA to thank for, this week there was something else announced. Transient electronics is the newest advance to come from the research group, as well as their partners at Tufts University, University of Illinois, and Northwestern. Transient — essentially dissolving — electronics are incredibly thin chips that melt away naturally after a given length of time.

There are some really interesting things going on here, the first being the composition of the electronics. They are made of “ultrathin sheets of silicon” and “magnesium encapsulated in silk”, in other words nothing particularly surprising. These are made to be impossibly thin, so that they are substantial enough to do their job but at the point where they are still biocompatible. Because silicon and magnesium are both found naturally in the human body the trace amounts of each material is absorbed without causing any harm.

A key aspect to all this is that it’s not too different from our standard electronics — it’s just thinner. Everything is still based on silicon, it’s just thin enough (around 20nm) that “biofluids” can dissolve everything in the course of days, weeks, or months instead of the thousands of years it would take a standard piece of silicon. (Yes, it would dissolve, though the practice is not advisable).

The key to the control of the erosion is the use of silk to cover the components. Silk, which is currently used in medical procedures such as surgical drains, can be designed to dissolve over a predetermined length of time, which would then set how long a circuit is protected before it starts to be broken down.

And how would such electronics be used? It seems that there are any number of medical applications, though one example cited was an implantable, non-antibiotic, programmable bactericide. Flexible sensors are another possibility as are a monitors for important bodily functions, such as brain and heart activity. Another example used was that of an implantable heater which could create a localized fever and prevent infection by making the area inhospitable to viruses and pathogens.

Dissoluble electronics are great, but two limitations that that have to be dealt with are control and power. Control is relatively easy (at least theoretically) because it can be done wirelessly. Power isn’t talk about much in the analysis of the paper but wireless charging is an option, and eventually everything might be powered by your body.

Another positive aspect of dissoluble electronics — one which is notable but minor in comparison to life-saving biocompatible devices — is the environmental benefit. A piece of electronics that dissolves when you are done with it would prevent the possibility of recycling after its active life, but it would stop the build up of e-waste over time. This is further off than simple implantable chips as it would require much more complex and powerful circuitry, but it could be an interesting solution in the future.